Coal burning boiler apparatus

Abstract

In a coal burning boiler apparatus, temperature of the pulverized coal to be fed to the boiler can be set depending on the property of the combustion coal, so that stable ignition and combustion can be made regardless of the property of the combustion coal fed.Provided are a coal burning boiler 1, a coal pulverizer 2 for pulverizing massive coal 6 into fine powder, a temperature sensor 18 for detecting temperature of the primary air 35 for entraining the pulverized coal to the coal burning boiler, regulators 9, 12, 13 and 14 for regulating the temperature of the primary air and a controller for controlling the primary air temperature regulators on the basis of detected result of the temperature sensor so as to make the primary air have a given temperature.

Description

TECHNICAL FIELD[0001]The present invention relates to a coal burning boiler apparatus using coal as fuel and particularly to a coal burning boiler apparatus which can realize proper combustion regardless amount of volatile portions of the coal.BACKGROUND ART[0002]In a coal burning boiler apparatus, massive coal is pulverized by a coal pulverizer into fine powder which is fed together with combustion air into a combustion furnace where it is ignited and burned. The ignition and combustion of the pulverized coal fed to the furnace are processed such that at first volatile portions produced by heating the pulverized coal is ignited and then the pulverized coal itself is ignited.[0003]Conventionally used in a coal burning boiler apparatus is bituminous coal, which has much volatile portions, is readily ignited and is stable in flame. In a coal burning boiler using bituminous coal as fuel, combustion air (primary air) entraining pulverized coal is heated by exhaust gas from a boiler, the...

AI Technical Summary

Benefits of technology

[0011]Excellent effects and advantages can be obtained in the invention. According to the invention, which comprises a coal burning boiler, a coal pulverizer for pulverizing massive coal into pulverized coal, a temperature sensor for detecting temperature of primary air entraining the pulverized coal to said coal burning boiler, means for regulating temperature of said primary air and a controller for controlling said regulating means on the basis of a detected result from said temperature sensor so as to make said primary air have a given temperature, the temperature of the primary air can be made suited for the property of the coal to obtain optimum combustion status regardless of the property of the coal. Thus, a low-quality coal may be used to decrease the running cost.

[0012]According to the invention, said primary air temperature regulating means may comprise a primary air feed pipe passing through an air preheater heated by exhaust gas from the boiler, a primary air bypass pipe bypassing said air preheater and joining into said primary air feed pipe, a first flow rate regulating damper arranged in said primary air feed pipe and a second flow rate regulating damper arranged in said primary air bypass pipe, said first and second flow rate regulating dampers being flow-rate controlled by said controller, which makes it possible to regulate the temperature of the primary air by means of the simple structure.

[0013]According to the invention, said controller may have data on properties of coals and data on spontaneous ignition temperatures corresponding to said properties of the coals, spontaneous ignition temperature corresponding to a property of the coal supplied being calculated on the basis of said data on the properties of the coals and said data on the spontaneous ignition temperatures, temperature of the primary air being set on the basis of a result of the calculation, which makes it possible to obtain optimum combustion status regardless of the property of the coal. Thus, low-quality coal may be used to decrease the running cost.

[0014]According to the invention, a further temperature sensor may be arranged on the inlet side of the coal pulverizer to conduct monitor for prevention of the temperature of the primary air flowing into said coal pulverizer from being higher than the given temperature.

Problems solved by technology

Pulverized coal with less volatile portions such as anthracite or semi-anthracite coal or oil coke has difficulty in ignition and is unstable in combustion.

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